Just ran across the most powerful GPS track visualization tool to date. The Magnalox.Net web site allows you to upload your GPS tracks and turn them into amazing visualization tools. Volker Kinkelin in Germany has created some of my most-wanted visualization tools including: animating your track (while showing speed and height graphs), colorization of your data (according to height or speed), automated geotagging of photographs taken during your track, and it allows you to perform story telling during the track. And, of course he provides the ability to view your track and story from within Google Earth.
As an example, I quickly uploaded the recent flying trip I wrote about here last week. Magnalox calls your uploaded tracks “magnalogs”. Once you load my magnalog it will immediately begin animating through the track. Below the graphs you can read my commentary for each event along the trip. You can just step through each story entry (under “Goto Story”) for greater control of the story.
Magnalox allowed me to easily generate a Google Earth file 
of the same magnalog (NOTE: I’ve made some slight modifications to my log to improve viewing). Each of my story entries are a placemark. If you double click the placemarks you can zoom in and see the better detail provided by Google Earth (e.g. try story entry “10”),
By the way, Magnalox is free to use, and has many powerful features. For example, if you click on the animated cursor in the log it allows you to open that waypoint in a variety of mapping tools including: Google Earth, Virtual Earth, Google Maps, Topozone, Multimaps, MSN, Geocaching.com, and more. Amazing! Great work Volker!
Volker also has written a powerful Pocket PC application which lets you interface your PDA with a GPS and uses the display to provide visualization of your track, integration with points of interest databases, and, of course, simple integration with Magnalox.
About Frank Taylor
Frank Taylor started the Google Earth Blog in July, 2005 shortly after Google Earth was first released. He has worked with 3D computer graphics and VR for many years and was very impressed with this exciting product. Frank completed a 5.5 year circumnavigation of the earth by sailboat in June 2015 which you can read about at Tahina Expedition, and is a licensed pilot, backpacker, diver, and photographer.